"Hardcore" players should at this point already be bored of 1-5 and there's actually quite a large amount of people who don't bother doing coil for one reason or another. Lowering the difficulty will allow people to experience more content then they have in the past, while the new content being released is still made difficult for the "Hardcore" players. The game isn't all about 1 demographic.

Personally, I enjoy this change. I can already do 1-4 easily and now I'll be able to get my last couple of WHM accessories and gear up my SMN/BRD much easier